Various types of pharmaceutical dosage forms are known for oral dosing. Pharmaceutical capsules are well known, generally being intended for oral dosing. Such capsules generally comprise an envelope wall of a pharmaceutically acceptable, e.g. orally ingestible, polymer material such as gelatin, although other materials for capsule walls, e.g. starch and cellulose based polymers are also known. Such capsules generally have soft walls made by making a film on a capsule former, which is then allowed to dry. Rigid walled capsules made by injection molding are also known, see for example U.S. Pat. Nos 4,576,284; 4,591,475; 4,655,840; 4,738,724; 4,738,817 and 4,790,881 (all to Warner Lambert). These disclose specific constructions of capsules made of gelatin, starch and other polymers, and methods of making them by injection molding of hydrophilic polymer—water mixtures. U.S. Pat. No. 4,576,284 specifically discloses such capsules provided with a cap which closes the capsule, and which is formed in situ on the filled capsule by molding. U.S. Pat. No. 4,738,724 discloses a wide range of rigid capsule shapes and parts.
Multi-compartment capsules, including those of the type where each compartment has different drug release characteristics, or for example, contains a different drug substance or formulation are also known, for example in U.S. Pat. No. 4,738,724 (Warner-Lambert); U.S. Pat. No. 5,672,359 (University of Kentucky); U.S. Pat. No. 5,443,461 (Alza Corp.); WO 95/16438 (Cortecs Ltd.); WO 90/12567 (Helminthology Inst.); DE-A-3727894, and BE 900950 (Warner Lambert); FR 2524311, and NL 7610038 (Tapanhony NV); FR 1,454,013 (Pluripharm); U.S. Pat. No. 3,228,789 (Glassman); and U.S. Pat. No. 3,186,910 (Glassman) among others. U.S. Pat. No. 4,738,817 discloses a multicompartment capsule with a similar construction to those of U.S. Pat. No. 3,228,789 and U.S. Pat. No. 3,186,910, made of a water-plasticized gelatin. U.S. Pat. No. 4,738,817 ('817) Witter et al., U.S. Pat. No. 4,790, 881 ('881), Wittwer et al., and EP 0 092 908, Wittwer, F., all discloses injection molded capsules prepared with gelatin and other excipients. Wittwer et al. '817 and '881 also prepare capsules with other hydrophilic polymers, such as hydroxypropylmethyl-cellulose phthalate (HPMCP), methylcellulose, microcrystalline cellulose, polyethylene glycol, cellulose acetate phthalate (CAP) and with polyvinylpyrrolidone. Both U.S. Pat. No. 4,790,881 and EP 0 091 908 propose other polymers having enteric properties suitable for use, including generally acrylates and methacrylates (Eudragits) although none are demonstrated and no specific details are provided.
Pharmaceutical dosage forms are also known which comprise a matrix of a solid polymer, in which a drug substance is dispersed, embedded or dissolved as a solid solution. Such matrixes may be formed by an injection molding process. This technology is discussed in Cuff G, and Raouf F, Pharmaceutical Technology, June (1998) pages 96-106. Some specific formulations for such dosage forms are disclosed in U.S. Pat. Nos. 4,678,516; 4,806,337; 4,764,378; 5,004,601; 5,135,752; 5,244,668; 5,139,790; 5,082,655; 5,552,159; 5,939,099; 5,741,519; 4,801,460; 6,063,821; WO 99/27909; CA 2,227,272; CA 2,188,185; CA 2,211,671; CA 2,311,308; CA 2,298,659; CA 2,264,287; CA 2,253,695; CA 2,253,700; and CA 2,257,547 among others.
U.S. Pat. No. 5,705,189, is directed to a group of co-polymers of methacrylic acid, methyl methacrylate and methyl acrylate, for use as thermoplastic agents in the production of drugs coatings, and capsules. No information is presented on the quality of the capsule formation with respect to warping or other distortions produced by the injection molding process. Nor is shear rate data presented for the viscosity/temperature figures of the emulsions presented therein.
It would also be desirable to prepare a pharmaceutical dosage form in which a pharmaceutically acceptable polymeric blend is extruded by hot melt into a suitable dosage form, or is injection molded into suitable dosage forms, which may be multicompartmental, such as in a capsule. This pharmaceutical polymeric composition as the dosage form may provide differing physio-chemical characteristics for each segment containing an active agent, such that a convenient dosage form can be optioned which may include a rapid dissolve, immediate, delayed, pulsatile, or modified release which can be produced by simply selecting the appropriate polymer(s) to be molded for each section.